GB1156609A - Device for the Lateral Guiding of a Travelling Tape - Google Patents

Abstract

1,156,609. Tape-guiding devices. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. 31 May, 1967 [19 July, 1966], No. 25115/67. Heading G5R. In a device for guiding a travelling tape, especially a magnetic tape, having means for exerting a pneumatic guiding force directed towards the desired position of the tape-two air pressure chambers which are subject to non- atmospheric pressure and which coact with one surface of the tape are disposed symmetrically with respect to the desired position of the centre line of the tape, and the tape when moving past the chambers partially closes them, so that any lateral deflection of the tape produces unequal closing of the chambers resulting in unsymmetrical curvature of the tape and its deflection back to its desired course. As shown in Figs. 3 and 4, magnetic tape 6 is guided along a guide member 7 in which are provided two rectangular chambers 8 separated from each other by a tape-supporting guide 9 in the form of a straight longitudinal projection below the centre line of the tape. The chambers 8 are connected to a vacuum source by openings 10. Thus the tape is curved downwardly. If the tape is displaced from its central position, shown, by an external force, the gaps 11 between the tape boundaries and the chambers 8 become unequal; thus one chamber is covered to a greater, and the other to a lesser, extent. In consequence the curvature of the tape over the one chamber increases, and the laterally inward force component F, Fig. 4, relative to that chamber, increases. The two force components F are thus unbalanced, and the tape is urged towards the central position again. The chambers 8 may be triangular or arcuate in plan instead of rectangular, while in Fig. 5c (not shown) the guide 9 extends diagonally. In Fig. 6 a magnetic tape 13 is guided over a member 12 of cylindrical cross-section through which air under pressure is supplied by channels 15 to two chambers 14. Apertures 17 are provided in the central tape-supporting guide 16 so that air can flow outwards therethrough to the underside of the tape to reduce friction. Half the apertures 17 are in communication with one chamber 14 and half with the other. The tape is curved upwardly. Uniform gaps 18 are formed as before.